Molding form



D. 'G. CLINE MOLDING FORM April 24, 1945..

Filed Aug. 2, 1945 INVENTOR. B YDLCA 51 27" 6. C4 //VA=.

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Patented Apr. 2 4, 1945 g QDelbertiG Cline, New Castle, Ind -assjgnorato H. l&l.A. .Selmer, Inc., Elkhart-zInd aacorpora-w g flpplioationAugust 2, 1943;SerialFNo. 491,005

ic aimfs. (ci ia-4s) This invention relates to improvements in-moldi-ngforms, "and --more"- particularly lid-"forms for -moldinghollow member=0fcomparatively large size from rubber; synthetic rubber, or likematerial. One example of the z-use of such forms-is "for molding fueleeellswfor use as liners ior the fuel"tanks zofairplanesiarmoredearsytankse small war boats, or -the like. i

Fuel mcells of this: character must obenmade in td-ifferentsizesiandshapeslto -fitsvvith accuracy. the toontonrs -of L thereoeivingcchambers therefor -.or

ref 1 fuel tanks 1 for which they may; form; liners,

a land wwhich s-differ -widelyi. according a to t: their inatended useand also sitheir .ulocations in and lithe structural characteristics,etc. of theimachinepr .melaiicle which said cellsi arelnrmountedal lThe:nvide :varietyvof; sizes andshapesiwhiohziara requ-iredamakeit,impractical to iuse metal zmolds, uwhichvwould :have tomeei: sectionalconstruction JWibh .provisions ix for ud-isassembling the; same 5110permit;removal thereoi lfromtheqinterior f the molded orlfinished-article; ill heyfactgr tof zorigeinal cost labqr cost toassemble and disassemble mo1dl:sections, and ot the great weight l-whichma t i nul i nend mov eethe m ldii i .lrlw ia l i l ltendh m e u r filire ,of heayyeduty hoisting equipment aH prevent (the ,,successful -useof ,imtal ,for molds, lOther 5' materials l preferably readilydecomposable maiterials, such as a corrugated paper Tlboard, gfiberboard molded plasten.onigypsum,tandicombinaati onsa of ,the ,latteruandpaper, .board,. have .i been employed with better results ,lthanmetalmolds,

. butiall of which, I am informed. havelobjections. .fIjhus paper. beardan'dlifiber .board moldsj require ,extensive vinterior bracing,arenfrequentlydisltorted and inaccurate, and .lca'nn'otl be manufactuiedlwit h reqilisitelpnifonnity; fMo Ided forms, made"from plasterorgybsum, or combinations not the same withpaperboard, etcl, aref'objecti onable"because of I.the l cost of {the necessary molds therefor} theweightthereof, and the. frantgible character thereof iwhich"makes 'themsubjectlto. breakage. and. chipping inhanliling and iIt'Lis :th eprimary" abject a this "invention. to

'radius contours ,andso' securedor assemble dwith iproyideamoldingform"whichovercomes the'bb- Tjections ofi'the"previousformsandretains the advantages of decomposable forms.

"Af further'objeotis to provide;a"molding form which i fabricated fromnormally fflatpreformed ,f'panels'pf decomposable ma-terial' which tendto "retaIWtheir'shape"butpessess-=atdeast asmall amountoffi'eiiibiii-ty, interconnected by arplu- 'rality of frame emeziibersihaving requisite =small J saidpanelsas to-maintaindesired overallcontour orshape, including-curved surfac'esy f said form and to*'beseparable upon decomposition or destruction'ofsaidpanels. l

A? further object is to, provide-a molding" form having surfacesthereofiinterrupted by irregular contours, "which is' fabricated I fromstandard preformeddecomposable pane1s-'which*'mount indi- "vidualcontoured elements of requisite 'size;=shape and location toconformwo"thedesiredl molding shape. s i i A further object is toprovide a moldingform fabricated "from normally flat r preformed"Edestructiblepanels to providethe faces of the mold andfrom"elongatedpreformed individual --strips interposed between andconnected to-"said panels 'to form the corners-aridedges of 'the moldingform whereihthepanels are held-in requisite curvature and braced by saidstrip and said strips are held in proper place and requisite cm'vatureandare braced by saidpanels. v

' Other objects will be" apparent from scription, drawing and appendedclaims. a In the drawing: f

Fig. 1 isa perspective view ofn-amolding -form. Fig. 2 isa transversesectional yiew taken on "lined-2 of Fig. 1.

-Fig. 3 is a fragmentary detail gsectionalmiew Fig. 4 isafragmentarydetail sectional view taken'on line 4-4 of Fig. '2. t

Fig. '5 is'a fragmentary detail =sectional iview taken online5-5'of-Fig. 1.

Fig. '6 is a fragmentary detail sectional-view illustrating a moldcondition similar -to that shown in -Fig.-5,* but embodying a modifiedconstruction. i 1

Fig. 7 isafragmentary sectional mg one type of panelmaterialwhichmaybe-used in fabricating the mold. l

Figr8is a fragmentary-perspective=view of one form of'moldingstrip.

other type'of molding strip. n

Fig. 10- is a "fragmentary perspective view: ofsa thirdtype of moldingstrip.

:Referringto the drawing, which illustrates the preferred embodiment: ofthe inventionithernuimeral l0 designates thetop (wall, I lithesidewalls, 12 the end walls, and l3 the :bottomwwallnofa molding form.i'I'hesewallslare formed;.shaped;or out inidesiredperimetric outlinesfrom anyasuit Mable :preformed :zpanel material 3 which possessestheifollowing properties :1: normal shape retention,

view illustrat- Fig. 9 is a fragmentaryside elevation of an at least asmall measure of flexibility, and a reasonable measure of strength, andwhich are either frangible, decomposable when subjected to hot water, orsusceptible of breakage or'destruction while dry, as along score lines.Diiferent types of commercially available materials possess theseproperties in varying degrees and are suitable for u'se, among which areplaster board or gypsum board, fiberboard or composition board such asthat known'in the trade as Celotex and Insulite, and corrugated paperboard. The last named material may require lamination of multiple sheetsthereof into a multiple thickness panel to provide the requisitestrength. It will be understood, of course, that the above list ofmaterials is simply illustrative, and not limiting. I prefer to use thematerial mentioned above and in addition a certain amount of workabilitywhen moistened, which property of workability is particularly valuablein the fabrication of forms of some shapes which are freqeuntlyrequired, such as forms having .ridged contours or reversely curvedfaces of slightly smaller radius than that to which the panel materialcan normally be flexed, but of larger radius than can conveniently oreconomically be provided by inserts, and the like.

The. various panels are interconnected by frame strips l6 which form theedges and corners of the molding form. The strips may be formed invarious sizes and shapes and from different materials, such as wood,metal, plaster or gypsum, or from thermo-plastic materials whoseplasticizing temperature or softening point exceeds the temperature atwhich the article to be.

molded is cured, dried or otherwise processed. One form of the strip isshown in Fig. 8, wherein the cross-sectional shape of the strip isillustrated as comprising an outer portion I! having converging faces I8merging with an intermediate transversely curved face portion IS, aninner portion20, and V-shaped grooves 2i in the opposite sides of thestrip and having one face perpendicular to and the other face parallelto the adjacent face 18. The grooves 2| are of a depth or size toreceive the margins of adjacent panels with the outer panel faces flushwith faces [8 and with the panel edges firmly abutting the groove walldefining one inner face of the outer strip portion 11. When properlypositioned, the panels and strips are interconnected by means of glue.sodium silicate, nails or other suitable means, although the use of anadhesive is preferred. In such assembly, the ends of the strips simplyabut, as at mitered end edges, ship-lap joints, finger joints, or thelike, and preferably are not se cured together to form a unitary frame,but are or shape the ridge.

joints 22 between said strip sections or between the same and otherframing units to be described hereinafter are illustrated in Fig. 4though other types of joints, such as finger joints, may be used. Dangerof damaging or puncturing the molded article during removal of thestrips is eliminated by such sectional construction, since short unitsor sections thereof can be manipulated and removed through small handholes in the molded article quite easily.

' It is essential that the corner of edge strips possess a certaindegree of longitudinal flexibility, whereas the cross-sectional shape ofthe strips described above tends to impart rigidity thereto. Therequisite flexibility can be provided by forming transverse kerfs 23 inthe inner portion 20 of the strips as shown in Fig. 9. Such kerfs maybespaced uniformly along the strip or a plurality thereof may becomparatively close spaced at points requiring increased curvature orcomparatively sharp bending.

An alternative form of strip, especially adapted for fabrication frommetal, is shown in Fig. 10. This form entails transverse bending orforming of sheet stock to provide a central portion 25 of requisitetransverse shape and curvature, web portions 26 preferably substantiallyperpendicular to the margins of a portion 25 or to the tangents of saidmargins, and flanges 21 projecting laterally perpendicularly outwardlyfrom said webs. A strip of this character may possess requisiteflexibility, or its flanges and webs may be transversely slitted alongits full length or at selected portions only to increase itsflexibility.

The strips may be of differentcross-sectional configurations asillustrated in Fig. 2, wherein the upper right hand cornerstrip'preseni's a curved surface of larger'radius than the lower lefthand corner strip, and wherein the lower right hand corner strip joinspanels whose marginal portions converge at an obtuse angle. The upperleft hand corner strip 28 in Fig. 2 is of a configuration to provide abeveled corner 29, also shown in Fig.1, and which extends for only'asmall portion of the length of the molding form. Strip 28 must be shapedat its'outer face to give the desired corner contour, including thecontour whichmerges with the contour of the rounded corner strips at theends thereof, and also must have the V-shaped grooves to receive theedges of the adjacent panels. Also, it may be necessary to provide themolding form with indented or inset portions as shown at the right inFig. 1 and also as shown in Fig. 3. Concavecorners at such indents or atvalleys can be provided by strips 30 having concave curved faces 3| andV- shaped panel receiving grooves 32 at opposite sides of said faces.

Sometimes a panel must be ridged, as at 33 in Fig. 1. If this ridge isnot too abrupt to permit bending of the panel to shape the same, it canbe constructed as shown in Fig. 5, wherein the frame strips 34 at theedge of the panel transverse of the ridge abut at said ridge. A sharperridge may require the construction shown in Fig. 6, wherein the ridgedface of the molding form is made from two panels 36 having a strip 31interposed therebetween, to extend along and define Many otherpossibilities exist for combining panels and strips to provide fordifferent shapes of the molding form, but it is believed. that thesepossibilities will be apparent from the combinations described andillustrated, of which they are merely variants.

A further important feature of the invention is its adaptability formolds having comparatively small contoured portions within theoutline ofone or more faces thereof. Two illustrationsof such contoured portionsare shownin Figs. 1 and 2. Thus, assume that the mold must provide forshaping of a neck around a hand hole, with an indented or inset portionof the wall of the molded article encircling such a neck. For such ashape or contour, thewall of the mold may have an opening, cut thereinat the outer margin of the desired indented portion. Within this openinga sectional insert 48 may be suitably secured, as by an adhesive. Theinsert sections may either be molded from thermo-plastic material,plaster, gypsum, etc., or may be carved milled or otherwise shaped ormachined from wood or metal. The insert includes a main body portion ofdesired contour, for example neck portion 4| and concave molding faceportion 42, upon which the contoured portion of the molded article is tobe formed, and a rearwardly ofi-set marginal flange 43 adapted to bearagainst the rear face of the panel, as H, which mounts the same.

so that the outer face of said panel will merge with molding faceportion 42. The parting plane between the sections of the insert 40preferably extends parallel tothe major dimension of said insert.

Another condition is illustrated by the contoured portion in the topwall of the molding form, which may include a pair of small necks 45each surrounded by convex portions 46 which merge with each other. Ifthe size of such a contoured portion is small, it may be formed in aone. part insert 41 mounted in the top wall ID as shown in Fig. 2.Insert 41 has body portion 48 of the desired molding contour, a marginalrearwardly off-set flange 49, and a wall 5llbetween the same to fitsnugly in a receiving opening in the panel "I, and is adhesively securedto said panel, all as described above relative to the sidewall insert40.

From the above description it wil be apparent that the instant moldingform posesses requisite strength for its purpose because of the mutuallybracing action of the strips and the panels, can be i fabricated in anyshape or contour and will hold that shape, is light in weight, can bedecomposed, broken or otherwise destroyed for quickly clean- The wall 44between the body portion and flange 43 fits snugly in the opening inpanel ll,

ing out the interior of the article molded therearound, is comparativelyinexpensive, and requires very little internal bracing to maintain itsdesired shape. The framing strips separate or may be separated when thepanels are decomposed or broken, and therefore can be manipulated andremoved from themolded article easily, quickly and without breakage.These strips hold the critical contours of the molding form within specistrips between said grooves being transversely contoured to define thecorners and edges of said form. i

2. A molding form as defined in claim 1, where- 'in said strips have aplurality of spaced transverse kerfsin the inner portion thereof toimpart flexibility thereto.

3. A hollow molding form having a comparatively small contoured portionin one wall thereof comprising a plurality of strong normally flatreadily destructible panels, a plurality of clone gated edge and cornerdefining strips of a difierent material interposed between and securedonly to said panels, one panel having an opening therein, and an insertfitting in said opening and having an exposed surface forming saidcontoured portion, said insert having a marginal flange secured to saidpanel and bearing against the inner face thereof around said opening. i

4. A hollow molding form comprising a plurality of preformed paperboardpanels, said panels having predetermined perimetric outlines, and i aplurality of elongated wood strips of configured cross-section havinglongitudinal grooves at opposite sides thereof, said strips receivingand being secured to the marginal portions of adjacent panels at saidgrooves to form a self-suporting hollow unit and each having a surfaceof predetermined configuration exposed between said panels and mergingwith the margins of the outer faces of said panels.

DELBERT G. CLINE.

